Known as Stoneman Willie, the man died in a local jail in 1895, where he suffered from kidney failure after being arrested for pickpocketing.

He was accidentally mummified by an undertaker who was experimenting with new embalming techniques, according to Auman's Funeral Home in Reading, Pennsylvania.

Dressed in a suit with a bow tie, Stoneman Willie is displayed in a coffin with a red sash across his chest. His hair and teeth remain intact, and his skin has taken on a leathery appearance.

Having given a fake name at the time of his arrest, the man's identity remained unknown for many years and local officials were unable to contact any relatives.

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But using historical documents, Stoneman Willie's real name has been identified and will be inscribed at the bottom of his tombstone when his body is buried on 7 October.

"We don't refer to him as a mummy. We refer to him as our friend Willie," funeral director Kyle Blankenbiller said.

"He has just been such an icon, such a storied part of not only Reading's past but certainly its present."

The funeral home had petitioned the state for permission to keep the body instead of burying it to monitor the process of the experimental embalming technique.

Ahead of the funeral, local residents filed onto the streets to celebrate Reading's 275th anniversary.

Stoneman Willie's coffin was carried on a motorcycle hearse, as part of a parade for the city.